Electronics Forum | Tue Nov 05 12:34:54 EST 2013 | rgduval
3-6 months, say, depending on the environment), I might consider a ramp-soak-spike profile to allow sufficient time for the flux to clean any potential contaminants. Cheers, ..rob
Electronics Forum | Wed Nov 06 03:51:28 EST 2013 | cuperpeter
Hi rob, Thank you very much for your response. Profiling was made exactly on the pad, which showed dewetting, so the values are mentioned for this pad. PCB's is about a week old. It is possible that the surface of pads is already oxidized? I will t
Electronics Forum | Tue Nov 05 09:57:45 EST 2013 | cuperpeter
Hello All, We have a problem with dewetting of solder paste. Problem is most visible on the pads without components (see attached pictures) and occurs randomly, 20% of PCB's. Pcb supplier sent us a cross-section of pads with thickness of Cu, Ni and
Electronics Forum | Wed Nov 06 10:03:59 EST 2013 | rgduval
Hi, Peter, I'm not an authority on surface finish thickness, and it's effect on reflowing, so, I can't advise on that front. If the boards are a week old, and ENIG, I would not suspect surface contamination. It's always a consideration, of course,
Electronics Forum | Wed Mar 11 10:58:58 EST 1998 | Earl Moon
| | What does the term "poor wetting" mean as a defect code ? "Poor" should mean unacceptable when surface (component or PCB solder termination areas) wetting does not provide acceptable solder joints. Unacceptable wetting of PCB solder termination
Electronics Forum | Thu May 19 07:06:59 EDT 2005 | py
have you some GND layer inside the pcb ? see IPC 610 A
Electronics Forum | Thu May 19 17:03:11 EDT 2005 | splice1
Hi all, There are no ground layers which makes the non wetting rate a bit confounding. The foam fluxer has not been cleaned in a while though, while there is a strong evidence of fluxing by running blank paper and looking up the top side
Electronics Forum | Tue Jul 30 08:37:39 EDT 2002 | davef
When you talk about 'poor wetting', 'dewett', 'no wets', etc.; are you seeing solder pulling back or away from the pad? Please describe the condition. Dewetting. The condition in the solder joint in which the liquid solder has not adhered intimate
Electronics Forum | Wed May 18 14:58:05 EDT 2005 | splice
Hi, I am having some PTH non wetting issues. Setup and chronology of events is explained: Set Up; Part: 1 MM pitch connector 378 pins Solder: Kester Ultra Pure 63/37 solder Pot; 250 C pre heat; Peak 94C top side Flux: Qualitek 775, Fluxer: foam T
Electronics Forum | Thu May 19 13:03:18 EDT 2005 | russ
On the non-wetted holes put a solder iron to them and see if they "bubble" if so, you have some outgassing in your PCB and they will need to be baked prior to assembly. If this is okay I would investigate the grnd layer that was mentioned. What is
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